Differentiation in corrosion performance of alumina forming alloys in alkali carbonate melts

• Alkali carbonate melts are promising high temperature thermal storage media. In this work five alumina forming alloys have been exposed to a ternary LiNaK carbonate melt and CO2 at 800 °C. The corrosion propagation was found to depend on the formation of a slow-growing LiAlO2 scale. Furthermore, the two polymorphs contributing to the LiAlO2 phase were monitored for up to 1000 h: a dense α-LiAlO2 scale and γ-LiAlO2 crystallites. We suggest a growth stress assisted formation of α-LiAlO2 relaxing into the outwards growing γ-LiAlO2 phase. This implies a deceleration of the α-LiAlO2 scale growth towards a steady state-thickness.

Ämnesord

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik -- Korrosionsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering -- Corrosion Engineering (hsv//eng)

Nyckelord

Phase transition

High temperature corrosion

Molten carbonates

Alumina forming alloys

Lithium aluminate

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